Effects of soil matric potential on potato growth under drip irrigation in the North China Plain

This research examines the affect of five soil matric potential (SMP) treatments [F1 (−15 kPa), F2 (−25 kPa), F3 (−35 kPa), F4 (−45 kPa), F5 (−55 kPa)] under drip irrigation conditions conducted in the North China Plain. The temporal and spatial SMP changes observed in the soil profile along with changes in potato root growth suggest that tensiometers placed immediately beneath the emitter (at 20 cm) can be effectively used in scheduling the drip irrigation regimen. Although rain affected soil water distribution during the growing season, the affects of SMP on potato growth were very clear. Crop evapotranspiration was highest for F2, decreasing thereafter to F1, F3, F4, and F5. Other potato growth properties such as crop height, leaf and stem water content, tuber bulk rate and grade, as well as WUE (water use efficiency) and IWUE (irrigation water use efficiency) suggest that an SMP of −25 kPa was the most favorable setting for potato production, while −15 kPa was too high and −45 kPa lead to severe water stress.